Time-shift image distribution system, time-shift image distribution method, time-shift image requesting apparatus, and image server

ABSTRACT

A time-shift image distribution system includes an image server and a time-shift image requesting apparatus. The image server includes a first communication unit configured to carry out communications with the time-shift image requesting apparatus, an image database configured to store image data of captured images in association with meta information for image data of a captured image matching search-condition information, and an image providing unit configured to provide the image data of the captured image detected by the searching unit to the time-shift image requesting apparatus. The time-shift image requesting apparatus includes a second communication unit configured to carry out communications with the image server, and a unit configured to send a search request including information representing an imaging time and information for identifying a subject image as search-condition information to the image server via the second communication unit.

CROSS REFERENCES TO RELATED APPLICATIONS

The present invention contains subject matter related to Japanese PatentApplication JP 2005-078623 filed in the Japanese Patent Office on Mar.18, 2005, the entire contents of which are incorporated herein byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a time-shift image distribution systemand a time-shift image distribution method for requesting an imageserver connected via a communication network to provide a time-shiftimage of a non-present time. The present invention also relates to atime-shift image requesting apparatus and an image server used in thesystem and method.

2. Description of the Related Art

Digital cameras for recording and saving captured images of objects onrecording media such as card-shaped memories or optical disks in theform of digital image signals are commonly used. Such digital camerasare described, for example, in Japanese Unexamined Patent ApplicationPublication No. 2004-343476 and Japanese Unexamined Patent ApplicationPublication No. 2004-121981.

In the digital camera market, various manufacturers are producing alarge number of new machines under competitions regarding resolution andprocessing speed. The digital cameras record and save images of presentviews currently displayed on viewfinders.

SUMMARY OF THE INVENTION

When capturing an image of an object, a user of a digital camerasometimes wishes to view a past image or a future image of the sameobject or in the same imaging direction at the same imaging location.However, with a digital camera currently available, it is not possibleto obtain an image of the past or the future, not of the present. Also,no system or scheme currently exists for obtaining such a past image orfor reserving a future image on the spot.

It is desired that a system that allows a user to obtain a past orfuture image of a specific subject be provided.

According to an embodiment of the present invention, there is provided atime-shift image distribution system. The time-shift image distributionsystem includes an image server; and a time-shift image requestingapparatus configured to request the image server to provide a time-shiftimage of a non-present time, the time-shift image requesting apparatusbeing connected to the image server via a communication network. Theimage server includes first communication means for carrying outcommunications with the time-shift image requesting apparatus via thecommunication network, an image database configured to store image dataof captured images in association with meta information includinginformation representing imaging times and information for identifyingsubject images captured, searching means for searching the imagedatabase on the basis of a search request received from the time-shiftimage requesting apparatus via the first communication means, the searchrequest at least including information representing an imaging time andinformation for identifying a subject image as search-conditioninformation, the searching means searching the image database for imagedata of a captured image matching the search-condition information, andimage providing means for providing the image data of the captured imagedetected by the searching means to the time-shift image requestingapparatus. The time-shift image requesting apparatus includes secondcommunication means for carrying out communications with the imageserver via the communication network, and means for sending a searchrequest including information representing an imaging time andinformation for identifying a subject image as search-conditioninformation to the image server via the second communication means.

According to the embodiment of the present invention, a user inputsinformation representing a non-present time, i.e., a past time or afuture time, to the time-shift image requesting apparatus. Then, thetime-shift image requesting apparatus generates a search requestincluding information representing the time and information foridentifying a subject image as search-condition information, and sendsthe search request to the image server via the communication network.

The image server searches the image database using at least theinformation representing the imaging time and the information foridentifying a subject image, included in the search-conditioninformation, to detect image data having corresponding meta information.

When the information representing the imaging time, included in thesearch-condition information, represents a past time, searching by thesearching means is executed. When image data matching thesearch-condition information is detected, the image providing meanssends the image data to the time-shift image requesting apparatus as aresult of searching, for example, via the communication network.

Thus, the user of the time-shift image requesting apparatus can readilyobtain a past image of a subject image by receiving the image data and,for example, displaying a corresponding image on a display screen.

On the other hand, when the information representing the imaging time,included in the search-condition information, represents a future time,the image server regards the search request as a search reservationrequest, and monitors whether image data matching the search-conditioninformation exists in the image database. When image data matching thesearch-condition information becomes available at a future time, theimage providing means provides the image data as a result of searching.

According to another embodiment of the present invention, there isprovided a time-shift image distribution method executed by an imageserver and a time-shift image requesting apparatus connected via acommunication network, the image server including an image databaseconfigured to accumulate image data of captured images in associationwith meta information including information representing imaging timesand information for identifying subject images, in which the time-shiftimage requesting apparatus requests the image server to provide atime-shift image of a non-present time to receive the time-shift imagefrom the image server. The time-shift image distribution methodcomprising the steps of establishing, by the time-shift image requestingapparatus, a communication path for carrying out communications with theimage server via the communication network; sending, by the time-shiftimage requesting apparatus, a search request to the image server throughthe communication path established, the search request includinginformation representing an imaging time and information for identifyinga subject image as search-condition information; searching, by the imageserver, the image database for image data of a captured image matchingsearch-condition information included in a search request received fromthe time-shift image requesting apparatus via the communication path,the search-condition information including information representing animaging time and information for identifying a subject image; andproviding, by the image server, the image data of the captured image,detected by the searching, to the time-shift image requesting apparatus.

According to another embodiment of the present invention, there isprovided a time-shift image requesting apparatus, connected to an imageserver via a communication network, for requesting the image server toprovide a time-shift image of a non-present time. The time-shift imagerequesting apparatus includes communication means for carrying outcommunications with the image server via the communication network; andmeans for sending a search request to the image server via thecommunication means, the search request including informationrepresenting an imaging time and information for identifying a subjectimage.

According to another embodiment of the present invention, there isprovided an image server, connected to a time-shift image requestingapparatus via a communication network, for receiving a request forproviding a time-shift image of a non-present time from the time-shiftimage requesting apparatus and providing the time-shift image to thetime-shift image requesting apparatus. The image server includescommunication means for carrying out communications with the time-shiftimage requesting apparatus via the communication network; an imagedatabase configured to accumulate image data of captured images inassociation with meta information including information representingimaging times and information for identifying subject images; searchingmeans for searching the image database on the basis of a search requestreceived from the time-shift image requesting apparatus via thecommunication means, the search request at least including informationrepresenting an imaging time and information for identifying a subjectimage as search-condition information, the searching means searching theimage database for a captured image matching the search-conditioninformation; and image providing means for providing image data of thecaptured image detected by the searching means to the time-shift imagerequesting apparatus.

According to these embodiments of the present invention, the user canreadily obtain a past or future image of a specific subject image.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram for explaining an overview of a time-shiftimage distribution system according to an embodiment of the presentinvention;

FIG. 2 is a diagram for explaining an example of imaging in thetime-shift image distribution system according to the embodiment;

FIG. 3 is a block diagram showing an example configuration of an imageserver in the time-shift image distribution system according to theembodiment;

FIG. 4 is functional block diagram for explaining processing functionsof the image server in the time-shift image distribution systemaccording to the embodiment;

FIG. 5 is a block diagram showing an example configuration of a digitalcamera as an example of a client apparatus in the time-shift imagedistribution system according to the embodiment;

FIG. 6 is a diagram for explaining an operation unit of the digitalcamera as the example of the client apparatus in the time-shift imagedistribution system according to the embodiment;

FIG. 7 is a part of a flowchart for explaining a processing operationexecuted by the digital camera as the example of the client apparatus inthe time-shift image distribution system according to the embodiment;

FIG. 8 is a part of the flowchart for explaining the processingoperation executed by the digital camera as the example of the clientapparatus in the time-shift image distribution system according to theembodiment;

FIG. 9 is a part of the flowchart for explaining the processingoperation executed by the digital camera as the example of the clientapparatus in the time-shift image distribution system according to theembodiment;

FIG. 10 is a flowchart of a processing operation executed by the imageserver in the time-shift image distribution system according to theembodiment;

FIG. 11 is a flowchart of a processing operation executed by the imageserver in the time-shift image distribution system according to theembodiment;

FIG. 12 is a flowchart of a processing operation executed by the imageserver in the time-shift image distribution system according to theembodiment;

FIG. 13 is a flowchart of a processing operation executed by the imageserver in the time-shift image distribution system according to theembodiment; and

FIG. 14 is a flowchart of a processing operation executed by the imageserver in the time-shift image distribution system according to theembodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Now, a time-shift image distribution system, and an image server and atime-shift image requesting apparatus in the system according to anembodiment of the present invention will be described with reference tothe drawings.

FIG. 1 is a block diagram showing the overall configuration of atime-shift image distribution system according to an embodiment of thepresent invention.

Referring to FIG. 1, in the time-shift image distribution system, animage server 1 and a client apparatus 2 are connected to each other viaa communication network 3, such as the Internet or a cellular phonenetwork. The client apparatus 2 is a time-shift requesting apparatusaccording to an embodiment of the present invention.

The image server 1 includes an image database 11. In the image database11, captured image data is stored in association with metadata. Themetadata includes, for example, a time of imaging (year, month, day,hour, minute, and second), a location of imaging (geographical locationand altitude), a direction of imaging, an angle of view, and a tiltangle of imaging (an upward or downward angle of the imaging directionwith respect to a horizontal plane). Hereinafter, the angle of view andthe angle of elevation or depression will be collectively referred to asa camera angle). In addition to these pieces of information, otherinformation for identifying a subject captured image (subject image),for example, the name of a particular architecture, such as “TokyoTower”, “Horyuji Temple”, or “Kaminarimon”, may be registered inassociation with an image including the architecture.

The names of these specific architectures may be manually input asinformation for identifying subject images. Alternatively, imagerecognition of a captured image is performed, and when an imageincluding such a specific architecture is recognized, the name of thearchitecture is automatically registered as meta information inassociation with the image data.

The client apparatus 2 in this embodiment has a function of imaging, afunction of displaying a captured image, and a function of carrying outnetwork communications. An example of the client apparatus 2 is acamera-equipped cellular phone. Another example of the client apparatus2 is an imaging device (digital camera or video camera) having afunction of wireless communications. Yet another example of the clientapparatus 2 is a camera-equipped personal digital assistant (PDA) or acamera-equipped personal computer.

In this embodiment, the client apparatus 2 has a function of uploadingimage data of a captured image of an object together with metainformation generated by the client apparatus 2 to the image server 1.However, the client apparatus 2 in this embodiment is configured so thateach user is allowed to determine whether to permit uploading of imagedata captured by the user to the image server 1. Thus, captured imagedata is uploaded to the image server 1 only when uploading is permitted.

As will be described later, the client apparatus 2 in this embodimentincludes units for automatically obtaining meta information, such as atime of imaging (year, month, day, hour, minute, and second), a locationof imaging (geographical position and altitude), a direction of imaging,and a camera angle. Furthermore, the client apparatus 2 in thisembodiment includes a unit for inputting names of architectures foridentifying subject images.

The client apparatus 2 in this embodiment is capable of sending a searchrequest for an image of a past time or a future time, not of a presenttime, to the image server 1. That is, as will be described later, theclient apparatus 2 includes a user interface for allowing a user toinput a past time or a future time, and also includes an operation unitfor sending a search request to the image server 1. In this embodiment,a search request is sent to the image server 1 by inputting a past timeor a future time and pressing a shutter button on the operation unit.

That is, by inputting a past time or a future time and then pressing ashutter button, the user achieves an effect substantially equivalent toan effect of capturing an image at the past time or the future time. Inresponse to the user's operation, the client apparatus 2 sends a searchrequest for the image of the past or future to the image server 1. Thesearch request sent from the client apparatus 2 includes informationrepresenting the past or future time and search-condition informationsuch as a location of imaging, a direction of imaging, and a cameraangle.

Furthermore, the user can input the names of specific architectures,such as “Tokyo Tower”, “Kaminarimon”, and “Horyuji Temple”, asinformation for identifying a captured image relevant to a searchrequest, so that the names of such specific architectures can beincluded in search-condition information.

Upon receiving a search request, the image server 1 analyzessearch-condition information to determine whether the conditionregarding the time of imaging specifies a past time or a future time.When the condition regarding the time of imaging specifies a futuretime, the image server 1 saves the search request as a searchreservation request so that the search reservation request will beexecuted at the specified future time.

On the other hand, when the condition regarding the time of imagingspecifies a past time, the image server 1 searches the image database 11using the search-condition information received. When a relevant pastimage is detected by the searching, the image server 1 sends image dataof the image detected to the client apparatus 2 at the source of thesearch request.

Upon receiving the image data detected by the searching, the clientapparatus 2 displays the image corresponding to the image data on adisplay, such as a liquid crystal display (LCD), as if the image of thepast time were captured by pressing a shutter button. At the same time,the client apparatus 2 records the image data on a recording medium forrecording captured data, such as a card-shaped memory or an opticaldisk.

Furthermore, at this time, when it has been specified by the user thatimage data of a present view captured by the client apparatus 2 is to bealso recorded, the image data captured at the present time is alsorecorded on the recording medium. At the client apparatus 2, instead ofallowing the user to specify whether to record image data of an imagecaptured at a present time, image data of an image captured at a presenttime may always be recorded.

Furthermore, when it has been permitted by the user at the clientapparatus 2 to upload image data to the image server 1, the clientapparatus 2 uploads image data actually captured at the present time bypressing a shutter button to the image server 1 together with metainformation such as a location of imaging, a time of imaging, adirection of imaging, and a camera angle.

The image server 1 stores the uploaded captured image data in the imagedatabase 11 in association with the meta information. In addition tothese pieces of information, other information, such as the names ofspecific architectures, such as “Tokyo Tower”, “Kaminarimon”, “HoryujiTemple”, may be registered in association with images including imagesof these architectures as contents thereof.

Of what has been described above, FIG. 2 shows a scheme of operationmainly regarding user's operations of a client apparatus in a case whereimaging-time information included in search-condition informationspecifies a past time.

More specifically, when a user wishes to obtain an image of an object ina certain direction captured in the past at a certain location, the uservisits the location. Then, using the client apparatus 2, a digitalcamera 21 in this case, the user inputs information representing thepast time, and sets the digital camera 21 and presses a shutter buttonin a desired imaging direction and at a desired camera angle.

At this time, the digital camera 21 is connected to the image server 1via the communication network 3. In response to the shutter operation,the search request described earlier is transmitted from the clientapparatus 2, i.e., the digital camera 21, to the image server 1, and apast image or past images detected by the searching are transmitted fromthe image server 1 to the digital camera 21. The past image or imagestransmitted from the image server 1 are displayed as a result of thesearching on a display screen of an LCD of the digital camera 21.

More specifically, the user inputs information representing a pat time,and sets the digital camera 21 in a desired direction to obtain a pastimage, thereby displaying a present view on a view finder implemented byan LCD as shown in an upper part of FIG. 2, and checks the imagingdirection and camera angle. When the user presses the shutter button inthis state, a past image provided from the image server 1 is displayedon the LCD screen of the digital camera 21 as if a past image werecaptured, as shown in a lower part of FIG. 2.

In what has been described above, when the shutter button is pressed, asearch request is sent to the image server 1 and data of a past imagerelevant to the search request is transmitted from the image server 1 tothe digital camera 21.

In this embodiment described below in detail, referring to FIG. 2, whenthe user inputs information representing a desired time to request andsets the digital camera 21 in a desired imaging direction and at adesired camera angle, a communication path is established between theimage server 1 and the client apparatus 2, i.e., the digital camera 21,and a search request is transmitted from the digital camera 21 to theimage server 1.

The image server 1 returns a search result at least includinginformation representing the presence or absence of image data capturedat the specified past time and matching the search condition such as theimaging direction and the camera angle. In this embodiment, in additionto the presence or absence of such image data, when the past timespecified has a certain range, for example, when a year range isspecified, information representing an approximate time of the relevantcaptured image in the year range is also transmitted. When a pluralityof relevant captured images exists, times at which the individual imageswere captured are displayed on the digital camera 21 as will bedescribed later.

Then, the user checks the past image returned in response to the searchrequest. When a plurality of images is returned, the user selectswhether to receive all the images or receive a specific captured image,and so forth, and then presses a shutter button. The operation of theshutter button in this case corresponds to a request for obtaining acaptured image corresponding to the search result selected.

In response to the captured-image obtaining request transmitted from theclient apparatus 2, i.e., the digital camera 21, the digital camera 21downloads the past image relevant to the obtaining request from theimage server 1.

As described earlier, the digital camera 21 displays the captured imagereceived on the display screen of the LCD and records the captured imageon a recording medium. When a plurality of images is requested andobtained, thumbnail images corresponding to the individual capturedimages may be displayed simultaneously on the LCD screen, or may bedisplayed by switching according to user's page shifting operations.

Example Hardware Configuration of Image Server

FIG. 1 shows an example hardware configuration of the image server 1implemented using a computer.

Referring to FIG. 3, a central processing unit (CPU) 101 is connected toa read-only memory (ROM) 102 and a random access memory (RAM) 103.Furthermore, an image database 11, a reservation-information database12, a search engine 13, a network interface 14, animage-transmission-queue storage unit 15, a calendar and timekeepingunit 16, an image reading unit 17, and a meta-information input unit 18are connected to a system bus 104.

As described earlier with reference to FIG. 1, in the image database 11,captured image data (image data content) is stored in association withmeta information, such as information representing a time of imaging(year, month, day, hour, minute, and second), information representing alocation of imaging, information representing a direction of imaging,and information representing a camera angle. In this embodiment, forexample, captured image data is compressed into a predetermined storageformat according to a predetermined compression scheme, and thecompressed image data is stored in the image database 11. Theassociation between captured image data and meta information is based onimage identification information (hereinafter referred to as image IDs),such as identification numbers, assigned individually to capturedimages.

The image server 1 receives captured image data and meta informationuploaded from the client apparatus 2 via the communication network 3through the network interface 14, and stores the captured image data andmeta information in the image database 11. Thus, in the image database11, images captured by various users in various locations, in variousimaging angles, and at various camera angles are constantly added andaccumulated.

The captured image data and meta information stored in the imagedatabase 11 are not limited to those uploaded from the client apparatus2 via the communication network 3.

For example, when a user brings in a sheet on which a captured image isprinted and a memo of meta information of the captured image, or when anadministrator of the image server 1 collected a sheet on which acaptured image is printed and meta information of the captured image,the captured image printed on the sheet is converted into captured imagedata, and the meta information is input manually. Then, the capturedimage data yielded by the conversion is stored in the image database 11in association with the meta information input.

In this embodiment, meta information stored in the image database 11includes information representing a user who provided the image, such asa user ID, a camera ID, a client ID, an address, a name, and an age, inassociation with each piece of image identification information (imageID).

The image reading unit 17 includes a scanner for reading the capturedimage printed on the sheet, and converting the captured image intocaptured image data. The meta information input unit 18 includes aninput operation unit for allowing manual input of meta information by anoperator or the like.

When an administrator or user of the image server 1 captures an image bya digital camera or a camera-equipped cellular phone terminal andrecords the image on a recording medium, if captured image data is readdirectly from the recording medium without using the communicationnetwork 3, and when meta information is recorded together, the metainformation is also read, and the captured image data and the metainformation are stored in the image database 11 in association with eachother. The image reading unit 17 includes a unit for reading capturedimage data and meta information from the recording medium.

When meta information is not recorded on the recording medium, or whenmeta information is to be added to meta information already recorded,meta information is manually input by an operator or the like using theinput operation unit of the meta-information input unit 18 so that themeta information is stored in the image database 11.

In the reservation information database 12, when search-conditioninformation included in a search request transmitted from a clientapparatus includes imaging-time information specifying a future time,the search request is stored as a search reservation request. At thistime, the search reservation request is stored in association withidentification information of the client apparatus that issued thesearch request. Similarly to the case of a search request withimaging-time information specifying a past time, the search requestincludes a location of imaging, a time of imaging (future time), adirection of imaging, a camera angle, and so forth as search-conditioninformation.

In this embodiment, a globally unique identifier (GUID), which allowsglobally unique identification, is used as the identificationinformation of the client apparatus 2. The GUID is used to record theclient apparatus 2 that has issued the search reservation request for afuture captured image and to provide an image in accordance with thesearch reservation request at the specified future time to the clientapparatus 2 having the GUID.

The search engine 13 searches information matching the search-conditioninformation included in the search request transmitted from the clientapparatus 2 from meta information stored in the image database 11. Whenmatching meta information is detected, the search engine 13 determinesthat the associated captured image data is captured image data thatserves as a result of the searching.

The image-transmission-queue storage unit 15 is used to execute thesearch reservation request including search-condition informationspecifying a future time as the time of imaging at the future time, andto reliably send the captured image obtained as a result of thesearching to the client apparatus 2 at the source of the searchreservation request.

More specifically, when the search reservation request is executed atthe specified future time and a captured image is obtained as a resultof the searching, and when the captured image data is sent to the clientapparatus 2 at the source of the search reservation request, the clientapparatus 2 may happen to be powered off so that it is not possible toestablish a communication path with the image server 1 via thecommunication network 3. In consideration of such a situation, imagedata obtained as a result of searching in response to the searchreservation request is stored in the image-transmission-queue storageunit 15. Then, at a suitable later time, image data obtained as s resultof searching in response to the search reservation request is sent tothe client apparatus 2 at the source of the search reservation requestin order of storage in the image-transmission-queue storage unit 15.

The calendar and timekeeping unit 16 generates calendar and timekeepinginformation represented by year, month, day, hour, minute, and second.The calendar and timekeeping information is used to determine whensearching is to be executed in accordance with a search reservationrequest transmitted from the client apparatus 2.

The ROM 102 stores a software program for receiving a search requesttransmitted from the client apparatus 2, causing the search engine 13 toexecute searching, accumulating search reservation requests in thereservation-information database 12, and sending captured image datarelevant to obtaining requests transmitted from the client apparatus 2to the client apparatus 2 at the source of the obtaining requests. TheCPU 101 executes processing according to the software program using theRAM 103 as a work area.

Functions and Operations of the Image Server 1

FIG. 4 mainly shows functions of the image server 1 having the hardwareconfiguration described above.

Referring to FIG. 4, a search request is transmitted from the clientapparatus 2 to the image server 1 via the communication network 3. Theimage server 1 receives the search request via the network interface104, and transfers the search request to a captured-image serviceproviding function unit 112 virtually through a path 111. Thecaptured-image service providing function unit 112 is a functionexecuted by the CPU 101 according to the software program stored in theROM 102.

The captured-image service providing function unit 112 extractsimaging-time information in search-condition information included in asearch request received, and checks whether the imaging time informationspecifies a past time or a future time.

When the imaging-time information specifies a past time, thecaptured-image service providing function unit 112 passes thesearch-condition information to the search engine 13 so that the searchengine 13 is activated to search the image database 11 for a capturedimage matching the search-condition information.

When a captured image matching the search-condition information isdetected by the searching, the search engine 13 passes at leastidentification information (image ID) and imaging-time information ofthe captured image detected by the searching to the captured-imageservice providing function unit 112.

The captured-image service providing function unit 112 forwards theidentification information (image ID) and the imaging-time informationreceived as a result of the searching onto the communication network 3through the path 111 and via the network interface 14 so that theidentification information and the imaging-time information aretransmitted to the client apparatus 2 at the source of the searchrequest.

After receiving the identification information and the imaging-timeinformation, when an operation for requesting obtainment of the capturedimage detected by the searching is performed (e.g., the shutter buttonis pressed) at the client apparatus 2, a request for obtaining thecaptured image detected by the searching is transmitted to the imageserver 1 via the communication network 3. The obtaining request includesidentification information of the captured image received by the clientapparatus 2 as a result of the searching.

In the image server 1, the captured-image service providing functionunit 112 receives the obtaining request via the network interface 14,reads image data corresponding to the image ID included in the obtainingrequest from the image database 11 via the search engine 13, and sendsthe image data to the client apparatus 2 via the network interface 14and the communication network 3.

When the search-condition information included in the search requestreceived specifies a future time as the time of imaging, thecaptured-image service providing function unit 112 of the image server 1regards the search request as a search reservation request, andregisters the search request in the reservation-information database 12.

The information registered in the reservation-information database 12 atthis time includes identification information of the client apparatus 2,i.e., the GUID in this example, an address (e.g., a uniform resourcelocator (URL)) on the communication network 3 for providing capturedimage data via the communication network 3, and search-conditioninformation such as imaging-time information representing a future time,a location of imaging, a direction of imaging, and a camera angle.

The image detected in response to the search reservation request may beprovided, for example, in the form of a printed image by mail, insteadof providing the image via the communication network 3. In considerationof this situation, it is desired to register an address, a mail address,and other information of the user of the client apparatus 2 in thereservation-information database 12.

At a timing when, for example, image data and meta information of a newcaptured image are additionally registered in the image database 11, thecaptured-image service providing function unit 112 checks whether asearch reservation request that is to be processed at the timing exists.When such a search reservation request exists, the captured-imageservice providing function unit 112 executes a routine for handling thesearch reservation request.

When a captured image matching the search-condition information isdetected by the routine for handling the search reservation request, thecaptured-image service providing function unit 112 reads the address ofthe client apparatus 2 that issued the search reservation request,stored in the reservation-information database 12, and registers a jobin the image-transmission-queue storage unit 15 to access the addressand send data of the captured image detected by the searching.

A transmission-control function unit 113 is implemented by a softwareprogram stored in the ROM 102. The transmission-control function unit113 checks the content of the image-transmission-queue storage unit 15,for example, at a predetermined interval, to check whether image data tosend has been queued. When it is determined that image data to transmithas been queued, the transmission control program transmits images inorder of storage in the image-transmission-queue storage unit 15. Thetransmission-control function unit 113 sends all image data that isstored in the image-transmission-queue storage unit 15 and yet to betransmitted while deleting image data that has been transmitted from theimage-transmission-queue storage unit 15.

Example Hardware Configuration of the Client Apparatus (Time-Shit ImageRequesting Apparatus)

FIG. 5 shows an example hardware configuration of the client apparatus2. The client apparatus 2 is an imaging device capable of carrying outwireless communications, i.e., a digital camera 21 in this example.Although this embodiment will be described in the context of a digitalcamera for capturing still images, the digital camera may also becapable of capturing moving images.

Referring to FIG. 5, in the digital camera 21 according to thisembodiment, a CPU 201 is connected to a ROM 202 and a RAM 203 via asystem bus 204, and the system bus 204 is connected to a camera module205, a camera operation input unit 206, an LCD controller 207 forcontrolling display on an LCD 208, a calendar and timekeeping unit 209,and a network interface 210.

Furthermore, the system bus 204 is connected to a non-volatile memory211 for recording captured images, a camera-GUID holding unit 212, asearch-condition input unit 213, an altitude sensor 214, a directionsensor 215, a tilt sensor 216, and a GPS positioning unit 217.

In the ROM 202, in addition to a program for carrying out imaging, aprogram for issuing a search request and an obtaining request to theimage server 1 and obtaining information transmitted in response to thesearch request and the obtaining request from the image server 1 anddisplaying and recording the information, a program for uploadingcaptured image data to the image server 1, and so forth are stored. Aswill be described later, the CPU 201 executes these programs stored inthe ROM 202 using the RAM 203 as a work area.

The camera module 205 includes an imaging device implemented by a chargecoupled device (CCD) imager or a complementary metal oxide semiconductor(CMOS) imager, an imaging optical system including an imaging lens, anda captured-image-signal processor. The camera module 205 outputscaptured image data in the form of digital signals to the system bus204.

The camera-operation input unit 206 includes a set of keys that are usedfor imaging, such as a zoom key and a shutter button. The CPU 201monitors which of these keys is operated in the camera-operation unit206, and executes processing in accordance with the key operatedaccording to programs stored in the ROM 202.

The LCD controller 207, under the control of the CPU 201 according toprograms stored in the ROM 202, controls display on the display screenof the LCD 208 connected thereto.

The calendar and timekeeping unit 209 generates calendar and timekeepinginformation representing year, month, day, hour, minute, and second. Thecalendar and timekeeping information is stored at the time of imaging asimaging-time information. When a timer operation is performed, a timerperiod is measured on the basis of timekeeping information supplied fromthe calendar and timekeeping unit 209.

The network interface 210 allows exchanging information with the imageserver 1 via the communication network 3.

The non-volatile memory 211 for recording captured images isimplemented, for example, by a flash memory, such as a card-shapedmemory. Alternatively, the non-volatile memory 211 may be implemented bya recording medium such as a digital versatile disc (DVD). Instead ofsuch a removable memory medium, the non-volatile memory 211 may beimplemented by a hard disk.

The camera GUID holding unit 212 is a storage unit for holding a cameraGUID that serves as globally unique camera identification information.As described earlier, when search-condition information includesimaging-time information specifying a future time, the camera GUID isused as identification information when the image server 1 rememberswhich digital camera (client apparatus) issued the search reservationrequest and when image data captured at the future time specified in therequest is transmitted to the digital camera 21 at the source of thesearch reservation request.

The search-condition input unit 213 includes operation keys with whichthe user inputs search-condition information included in a searchrequest for a past or future captured image, transmitted to the imageserver 1. FIG. 6 is a diagram showing an example of the search-conditioninput unit 213 included in the digital camera 21 according to thisembodiment. FIG. 6 shows a back side of the case of the digital camera21 opposite to a front side on which an imaging lens is provided. Inthis example, the keys of the search-condition input unit 213 areprovided on a side of a screen 208D of the LCD 208 on the back side ofthe digital camera 21.

In this embodiment, for example, as shown in FIG. 6, thesearch-condition input unit 213 includes a date dial key 301 forinputting imaging-time information (year, month, day, and time)representing a time of imaging, a range specifying dial key 302 forspecifying a range of searching with reference to the time specified bythe date dial key 301, a year-range zooming key 303, an auto search key304, and a cross-shaped cursor key 305.

In this example, the date dial key 301 has a donut-shaped part 301 a anda central circular part 301 b. When the donut-shaped part 301 a isoperated in the circumferential direction, the year, month, day, andtime specified are changed forward or backward in accordance with thedirection of operation. At this time, the year, month, day, and timespecified using the date dial key 301 are displayed on the LCD screen208D as specified date indication 401 as shown in FIG. 6. The user canfix the specified year, month, day, and time by pressing the centralcircular part 301 b of the date dial key 301. That is, the centralcircular part 301 b of the date dial key 301 serves as a specificationfixing key.

Similarly, the range specifying dial key 302 has a donut-shaped part 302a and a central circular part 302 b. When the donut-shaped part 302 a isoperated in the circumferential direction, the specified range of dateand time increases or decreases in accordance with the direction ofoperation. At this time, the range of date and time specified using therange specifying dial key 302 is displayed as date range indication 402on the LCD screen 208D as shown in FIG. 6.

The user can fix the specified range of date and time by pressing thecentral circular part 302 b of the range specifying dial key 302. Thatis, the central circular part 302 b of the range specifying dial key 302serves as a range specification fixing key.

In the example shown in FIG. 6, with respect to the date and timerepresented by the specified date indication 401, the range of date andtime specified by the date range indication 402 is used as imaging-timeinformation included in search-condition information.

In this example, with respect to the date and time represented by thespecified date and time indication 401, a range of preceding orsucceeding period corresponding to the year, month, day, and timespecified by the range specifying dial key 302 is used as imaging-timeinformation included in search-condition information. Alternatively,with respect to the date and time represented by the specified dateindication 401, a range of succeeding period corresponding to the year,month, day, and time specified using the range specifying dial key 302or a range of preceding period corresponding to the year, month, day,and time specified using the range specifying dial key 302 may be usedas imaging-time information included in search-condition information.

Yet alternatively, a range of years may be used as imaging-timeinformation included in search-condition information. For example, arange specification such as the year 1998 or from the year 1998 to theyear 2000 may be used as imaging-time information included insearch-condition information.

In a lower part of the LCD screen 208D shown in FIG. 6, in thisembodiment, a bar (hereinafter referred to as a navigation bar) 403indicating how many years the captured images accumulated in the imageserver 1 date back to is displayed.

That is, in this embodiment, when the digital camera 21 sends a searchrequest including imaging-time information to the image server 1, theimage server 1 searches captured images matching search-conditioninformation such as an imaging location and an imaging direction, notonly within the range of imaging time specified as described above. Whena plurality of captured images is detected by the searching, the imageserver 1 sends information representing imaging-time information andidentification information of the individual captured images assearch-result information.

Upon receiving the search-result information, the digital camera 21indicates the existence of the individual captured images by verticalbar marks 404. That is, the navigation bar 403 represents, for example,a range of 20 to 30 years by a horizontal bar with respect to the dateand time specified using the date dial key 301. In the example shown inFIG. 6, the navigation bar 403 represents a range from the year 1980 tothe year 2004.

The range of years represented by the navigation bar 403 can be changedby operating the year-range zooming key 303. More specifically, in thisembodiment, the year-range zooming key 303 is a seesaw key. That is,when the year-range zooming key 303 is operated in the “−” direction,although the length of the navigation bar 403 does not change, the rangeof years represented by the navigation bar 403 becomes narrower (withrespect to the same specified date).

On the other hand, when the year-range zooming key 303 is operated inthe “+” direction, although the length of the navigation bar 403 doesnot change, the range of years represented by the navigation bar 403becomes wider (with respect to the same date specified).

In the navigation bar 403, vertical bar marks 404 are displayed atpositions corresponding to the imaging times of the individual capturedimages included in the search-result information transmitted from theimage server 1, thereby notifying the user that captured images matchingsearch conditions except for imaging time exist at the positions of thevertical bar marks 404.

In this embodiment, the range of imaging time represented by thespecified date indication 401 and the range indication 402 is presentedto the user by specified range frame indication 405. That is, in thenavigation bar 403, the date range enclosed in the frame of thespecified range frame indication 405 is the range currently specified assearch-condition information regarding the imaging time.

As shown in FIG. 6, in this embodiment, of the search-result informationobtained from the image server 1, the number of captured images includedin the specified range frame indication 405 is displayed asnumber-of-matching-image indication 406. In the example shown in FIG. 6,it is indicated that three images matching the search condition existsin the specified range frame indication 405. When no captured imagematching the search condition exists in the image server 1, “0” or“None” is displayed as the number-of-matching-image indication 406.

When the LCD 208 is a color LCD, preferably, for example, vertical barmarks indicating existence of captured images matching search-conditioninformation are displayed in red and the specified-range frameindication 405 is displayed in green so that the ease of visualrecognition is improved. This serves to improve the ease of operationfor the user.

In this embodiment, the position of the specified-range frame indication405 can be moved leftward or rightward by operation of the cross-shapedcursor key 305, thereby changing imaging time and imaging time rangeincluded in search-condition information. That is, when the position ofthe specified-range frame indication 405 is moved leftward or rightwardby operation of the cross-shaped cursor key 305, the indications 401 and402 change in accordance with the position of the specified-range frameindication 405.

That is, in this embodiment, imaging time and imaging time rangeincluded in search-condition information may be specified by changingthe position of the specified-range frame indication 405 on thenavigation bar 403 using the cross-shaped cursor key 305 instead ofdirect specification using the date dial 301 and the range specifyingdial key 302.

In this embodiment, when a past time is specified as imaging-timeinformation included in search-condition information and the shutterbutton is pressed, the operation virtually achieves the effect ofcapturing an image at a past time in the frame of the specified-rangeframe indication 405.

In this embodiment, when the user inputs information representing a pasttime as imaging information included in search-condition information, orwhen a past time that has been input is changed, or when parameters inthe search condition information such as an imaging location, an imagingdirection, and an imaging angle are changed as will be described later,the imaging device automatically establishes a communication path withthe image server 1 via the communication network 3 and sends a searchrequest.

However, it is difficult to constantly maintain a communication pathbetween the imaging device and the image server 1. Thus, it is desiredthat the user be allowed to connect to the image server 1 and to send asearch request when the user so desires. The auto search key 304 isprovided for this purpose.

Alternatively, it is possible to access the image server 1, send asearch request, receive search-result information from the image server1, and display the navigation bar 403 only when the user operates theauto search key 304.

The altitude sensor 214 detects the altitude of the current location ofthe digital camera 21, and sends information representing the altitudedetected onto the system bus 204.

The direction sensor 215 detects the direction of an optical axis of thelens optical system of the camera module 205, i.e., the direction ofimaging, and sends information representing the imaging directiondetected onto the system bus 204.

The tilt sensor 216 detects the angle of the direction of the opticalaxis of the lens optical system of the camera module 205 with respect toa horizontal plane (an angle of elevation or depression), i.e., anupward or downward angle of the imaging direction of the digital camera21 (what is referred to as an imaging angle), and sends informationrepresenting the imaging angle detected onto the system bus 204.

The GPS positioning unit 217 receives electromagnetic waves transmittedfrom GPS satellites to detect a current location of the digital camera21, and sends information representing the current location detectedonto the system bus 204.

In this embodiment, as will be described later, the altitude informationfrom the altitude sensor 214, the imaging-direction information from thedirection sensor 215, the imaging-angle information from the tilt sensor216, and the location information from the GPS positioning unit 217 arerecorded in the non-volatile memory 211 as meta information of therelevant captured image.

When a search request is sent to the image server 1, in addition to theimaging-time information described earlier, the altitude informationfrom the altitude sensor 214, the imaging-direction information from thedirection sensor 215, the imaging-angle information from the tilt sensor216, and the location information from the GPS positioning unit 217 areincluded in search-condition information.

Furthermore, in this embodiment, the user is allowed to determinewhether or not to upload an image captured by the digital camera 21 tothe image server 1, and information representing the setting is storedin a non-volatile memory (not shown), which may be a memory backed up bya battery. When the shutter button is pressed, the setting informationis checked, and the captured image is uploaded to the image server 1together with meta information to the image server 1 when uploading ispermitted.

Instead of holding setting predefined by the user as to whether topermit uploading to the image server 1, each time the user presses theshutter button, a message may be displayed on the LCD screen 208D to askthe user whether to permit uploading of data of the captured image tothe image server 1, prompting the user to choose whether to permituploading.

As described above, in the digital camera 21 according to thisembodiment, the location and angle of imaging by the user are recognizedby the altitude sensor 214, the direction sensor 215, the tilt sensor216, and the GPS positioning unit 217 mounted on the digital camera 21.The digital camera 21 issues a search request to the image server 1using the conditions recognized and a non-present imaging time such as apast or future year as search conditions, thereby searching the imageserver 1 on the Internet for past images captured in the year andmatching the search conditions.

When the user presses the shutter button, an image of the specified yearrange is transmitted from the image server 1. This is as if an image ofthe past or the future were taken.

As for a future image, a reservation is registered in the image server1, so that an image captured at a date and time specified in thereservation will be transmitted to the digital camera 21.

Thus, a virtual time-machine camera that allows not only capturing apresent view but also allows imaging beyond restriction of time can beimplemented.

Example Procedure for Obtaining Past Image

Now, a procedure for obtain a past image using the digital camera 21configured as described above will be described, including relationshipwith the image server 1.

An image shown in an upper part of FIG. 2 is an image that is displayedwhen the user uses the LCD screen 208D as a viewfinder. In this state,the user can specify a desired year, month, and day of imaging byoperating the date dial key 301 of the digital camera 21.

When the digital camera 21 is in an imaging mode, the altitude sensor214, the direction sensor 215, the tilt sensor 216, and the GPSpositioning unit 217 constantly obtain data. The digital camera 21issues a search request to the image server 1 as to whether an imagematching search-condition information, such as a specified date and acurrent location and imaging direction of the digital camera 21, exists.

On the basis of a search result returned from the image server 1, thenavigation bar 403 is displayed on the LCD screen 208D, and the numberof captured images existing at the image server 1 and matching thespecified date and time range is displayed.

When the user checks the result of searching by the image server 1through the navigation bar 403 and presses the shutter button, imagesfalling in the specified year range are transmitted from the imageserver 1. This is as if images of the past were taken.

For example, referring to FIG. 2, assuming that the current year is2005, when the year-range setting for captured images to request via thedigital camera 21 is 10 years before, i.e., 1995, and the digital camera21 is set at such an angle that the image shown in the upper part ofFIG. 2 is covered, it is indicated on the LCD screen 208D that onecorresponding image exists at the image server 1. When the shutterbutton is pressed in this state, an image of the year 1995, shown in alower part of FIG. 2, is obtained.

At the same time, an image of the present view, shown in the upper partof FIG. 2, is also captured. When the setting of the digital camera 21permits uploading, the image of the present view is uploaded to theimage server 1 as data of a new captured image.

Example Procedure for Obtaining Future Image

When the user specifies a future time as an imaging time insearch-condition information, i.e., when a future year range isspecified, no corresponding captured image exists at the time when theshutter button of the digital camera 21 is pressed, so that it is notpossible to obtain an image immediately. Since a future image does notcurrently exist, a reservation for the image providing service of theimage server 1 is made. When the specified date and time has come, if animage matching the search condition exists, the image is transmittedfrom the image server 1 to the digital camera 21 that has made thereservation or to another terminal specified by the user.

Since it is often the case that no image corresponding to a future imageexists when a range up to a specific date is specified, it is allowed toset a range on and after a specific date or to set a considerably broadrange.

Also when the shutter button is pressed with a future time specified,when the setting of the digital camera 21 permits uploading, the digitalcamera 21 captures an image of the present view and uploads the imagewith meta information to the image server 1.

Flowcharts of Operations of Digital Camera (Time-Shit Image RequestingApparatus)

Next, operations of the digital camera 21 for issuing a search requestand for issuing an obtaining request to the image server 1 and routinesfor handling these requests will be described with reference toflowcharts shown in FIGS. 7 to 9.

In step S101, when the user issues an instruction for entering theimaging mode, the CPU 201 of the digital camera 21 first checks whetherto enter a time-shift imaging mode for capturing an image of a past timeor a future time, not a present time. Whether to enter the time-shiftimaging mode is determined on the basis of, for example, whether anon-present time is specified by the date dial key 301. Alternatively, akey for specifying either a time-shift imaging mode or an ordinaryimaging mode may be provided so that whether to enter the time-shiftimaging mode can be determined on the basis of a user's operation of thekey.

When it is determined in step S101 not to enter the time-shift imagingmode, in step S102, the CPU 201 executes a processing routine of entersthe ordinary imaging mode and executes a processing routine of theordinary imaging mode.

In the ordinary imaging mode, the CPU 201 displays an image of an objecton the LCD screen 208D using the LCD screen 208D as an electronicviewfinder. When the user presses the shutter button, the CPU 201executes processing for actually capturing an image of the object andstoring captured image data in the non-volatile memory 211 for recordingcaptured images. At this time, when the digital camera 21 is in theimaging mode, the altitude sensor 214, the direction sensor 215, thetilt sensor 216, and the GPS positioning unit 217 constantly obtaindata. The altitude data, the imaging-direction data, the camera-angledata, the imaging-location data, and the current date and time obtainedfrom the calendar and timekeeping unit 209 are stored in thenon-volatile memory 211 for recording captured images, in association(on the basis of the image ID) with the captured image data as metainformation of the captured image.

At this time, when the setting of the digital camera 21 permitsuploading to the image server 1, the digital camera 21 uploads thecaptured image of the present view and meta information to the imageserver 1 via the communication network 3.

When it is determined in step S101 to enter the time-shift imaging mode,the CPU 201 obtains information representing a current location from theGPS positioning unit 217 in step S103, obtains information representinga current altitude from the altitude sensor 214 in step S104, obtainsinformation representing an imaging direction from the direction sensor215 in step S105, and obtains camera tilt-angle information from thetilt sensor 216 in step S106.

Furthermore, in step S107, the CPU 201 obtains imaging-time informationspecified by the user using the date dial key 301, the cross-shapedcursor key 305, or the like. Also, in step S108, the CPU 201 obtainsinformation representing a search range regarding the imaging time, setby the user using the range specifying dial key 302 or the like.

Then, in step S109, the CPU 201 checks whether the pieces of informationobtained from the sensors 214 to 216 and the GPS positioning unit 217 orthe specification of imaging time or range has been changed. When it isdetermined in step S109 that the pieces of information obtained from thesensors 214 to 216 and the GPS positioning unit 217 or the specificationof imaging time or range has not been changed, in step S110, the CPU 201checks whether a predetermined time has elapsed.

When it is determined in step S110 that the predetermined time haselapsed, returning to step S103, the CPU 201 obtains information such assensor values and an imaging time.

When it is determined in step S110 that the predetermined time has notelapsed, in step S121 shown in FIG. 8, the CPU 201 checks whether theauto search key 304 has been operated by the user. When it is determinedthat the auto search key 304 has not been operated, returning to stepS110, the CPU 201 monitors elapse of the predetermined time.

When it is determined that the auto search key 304 has been operated,the CPU 201 obtains information representing a current location from theGPS positioning unit 217 in step S122, obtains information representinga current altitude from the altitude sensor 214 in step S123, obtainsinformation representing an imaging direction from the direction sensor215 in step S214, and obtains information representing a camera tiltangle of the digital camera 21 from the tilt sensor 216 in step S125.

Furthermore, in step S126, the CPU 201 obtains information representingan imaging time specified by the user using the date dial key 301, thecross-shaped cursor key 305, or the like. Also, in step S127, the CPU201 obtains an imaging-time search range specified by the user using therange specifying dial key 302 or the like.

After step S127, the procedure proceeds to step S111 shown in FIG. 7.The procedure also proceeds to step S111 when it is determined in stepS109 that the pieces of information obtained from the sensors 214 to 216or the specification of imaging time or range has been changed.

In step S111, the CPU 201 determines whether the imaging time specifiedby the user is a past time or a future time. When it is determined instep S111 that the imaging time specified by the user is a past time, instep S112, the CPU 201 accesses the image server 1 via the networkinterface 210 and the communication network 3 to establish acommunication path with the image server 1. In this embodiment, anaddress of the image server 1 on the communication network 3 is storedin advance in the digital camera 21, and the address information is usedto access the image server 1 automatically.

When a communication path with the image server 1 is established asdescribed above, in step S113, the CPU 201 sends a search request to theimage server 1, the search request including the pieces of informationobtained from the sensors 214 to 216 and the GPS positioning unit 217and the specification of imaging time and range as search-conditioninformation.

In response to the search request, search-result information is returnedfrom the image server 1 as described earlier. Upon receiving thesearch-result information, in step S114, the CPU 201 displays thenavigation bar 403, and displays the number of captured images matchingthe search-condition information on the LCD screen 208D. In step S115,the CPU 201 stores the image IDs of all the captured images matching thesearch-condition information, transmitted from the image server 1.

Then, in step S131 shown in FIG. 8, the CPU 201 checks whether theshutter button has been pressed. When it is determined that the shutterbutton has not been pressed, proceeding to step S121, the CPU 201executes subsequent steps described earlier.

On the other hand, when it is determined in step S131 that the shutterbutton has been pressed, in this embodiment, in step S132, the CPU 201captures an image of the present view displayed on the LCD screen 208Dto obtain image data, also obtains meta information described earlier,and writes the image data and the meta information to the non-volatilememory 211 for recording captured images.

In step S133, the CPU 201 sends an image obtaining request for obtainingcaptured images matching the search-condition information to the imageserver 1, the image obtaining request including the image IDs stored instep S115.

In response to the image obtaining request, image data of capturedimages identified by the image IDs is transmitted from the image server1. The CPU 201 receives the image data in step S134, and displays theimages on the LCD screen 208D and writes the image data to thenon-volatile memory 211 for recording captured images in step S135.

In step S136, the CPU 201 checks whether the setting permits uploadingof captured images. When it is determined that the setting permitsuploading, in step S137, the CPU 302 sends an image uploading request tothe image server 1, and sends image data and meta information of thecaptured image of the present view recorded in step S132 to the imageserver 1. The CPU 201 then exits the processing routine.

When it is determined in step S136 that the setting does not permituploading of captured images, the CPU 201 skips step S137 andimmediately exists the processing routine.

When it is determined in step S11 shown in FIG. 7 that the imaging timespecified by the user is a future time, in step S141 shown in FIG. 9, asopposed to the case of a past time, the CPU 201 does not send a searchrequest to the image server 1 at this time, and checks whether theshutter button has been pressed.

When it is determined in step S141 that the shutter button has not beenpressed, returning to step S110, the CPU 201 executes subsequent stepsdescribed earlier.

On the other hand, when it is determined in step S141 that the shutterbutton has been pressed, in this embodiment, in step S142, the CPU 201captures an image of the present view currently displayed on the LCDscreen 208D to obtain image data, also obtains meta information, andwrites the image data and the meta information to the non-volatilememory 211 for recording captured images. Then, in step S143, the CPU201 accesses the image server 1 via the network interface 210 and thecommunication network 3 to establish a communication path with the imageserver 1.

After establishing a communication path with the image server 1, in stepS144, the CPU 201 sends a search reservation request to the image server1, the search reservation request including the pieces of informationobtained from the sensors 214 to 216 and the GPS positioning unit 217and the specification of imaging time and range as search-conditioninformation.

In step S145, the CPU 201 checks whether the setting permits uploadingof captured images. When it is determined that the setting permitsuploading, in step S146, the CPU 201 sends an image uploading request tothe image server 1, and sends the image data and meta information of thecaptured image of the present view, recorded in step S142, to the imageserver 1. The CPU 201 then exits the processing routine.

When it is determined in step S145 that the setting does not permituploading of captured images, the CPU 201 skips step S146 andimmediately exits the processing routine.

In steps S136 and S145, whether uploading is permitted is checkedassuming that the user specifies in advance whether to permit uploadingof captured images to the image server 1. Alternatively, as describedearlier, each time the user presses the shutter button, the user may beasked whether to permit uploading of the captured image to the imageserver 1, for example, via the LCD screen 208D, so that whether toupload the captured image can be determined in accordance with a user'sresponse as to whether to permit uploading.

Flowcharts of Operations of the Image Server 1

Next, processing operations executed by the image server 1 will bedescribed with reference to flowcharts shown in FIGS. 10 to 14.

In step S201, the CPU 101 of the image server 1 checks whether aconnection request for establishing a communication path from the clientapparatus 2, e.g., the digital camera 21, has been received. When it isdetermined that a connection request for establishing a communicationpath from the client apparatus 2 has been received, in step S202, theCPU 101 establishes a communication path with the client apparatus 2.

In step S203, the CPU 101 checks whether a search request (a searchrequest including a past imaging time in search-condition information)from the client apparatus 2 has been received. When it is determinedthat a search request has been received, in step S204, the CPU 101executes a searching routine for handling the search request. Thesearching routine will be described later.

When it is determined in step S203 that a search request from the clientapparatus 2 has not been received, in step S205, the CPU 101 checkswhether an image obtaining request has been received. When it isdetermined that an image obtaining request has been received, in stepS206, the CPU 101 executes a processing routine for handling the imageobtaining request.

When it is determined in step S205 that an image obtaining request fromthe client apparatus 2 has not been received, in step S207, the CPU 101checks whether a search reservation request (a search request includinga future imaging time in search-condition information) has beenreceived. When it is determined that a search reservation request hasbeen received, in step S208, the CPU 101 executes a processing routinefor handling the search reservation request.

Instead of letting the image server 1 determine whether a search requestis a search reservation request on the basis of whether imaging-timeinformation included in search condition information represents a futuretime, in a search request, the client apparatus 2 may includeinformation representing distinction between a search request for a pastcaptured image and a search reservation request for a future capturedimage.

When it is determined in step S207 that a search reservation requestfrom the client apparatus 2 has not been received, in step S209, the CPU101 checks whether an uploading request for uploading a captured imagehas been received. When it is determined that an uploading request hasbeen received, in step S210, the CPU 101 executes a processing routinefor handling the uploading request.

When it is determined in step S209 that an uploading request from theclient apparatus 2 has not been received, in step S211, the CPU 101executes other processes.

FIG. 11 is a flowchart of a searching routine for handling a searchrequest, executed by the image server 1 in step S204 described earlier.

First, in step S301, the CPU 101 decodes a packet of the search requesttransmitted from the client apparatus 2. Then, in step S302, the CPU 101obtains search-condition information regarding an imaging location, animaging direction, an altitude, and a camera angle, included the packetof the search request. Furthermore, in step S303, the CPU 101 obtainssearch-condition information regarding imaging time, i.e., a range ofimaging time, included in the packet of the search request.

In step S304, the CPU 101 searches for a captured image matching thesearch-condition information obtained in steps S302 and S303 withreference to the meta information stored in the image database 11. Inthis embodiment, the searching is performed not only within the range ofimaging time obtained in step S303 but over a predetermined periodextending before and after the range of imaging time. This is soarranged in consideration of the manner of representation on thenavigation bar 403 so that the existence of captured images is indicatednot only within the specified range of imaging time but over a rangeextending before and after the specified range. Thus, when therepresentation on the navigation bar 403 need not be considered,searching may be executed only within the imaging-time range obtained instep S303.

In step S305, the CPU 101 sends an image ID and imaging-time informationof the captured image matching the search-condition information,detected in step S304, to the client apparatus 2 at the source of thesearch request. When a plurality of captured images matching thesearch-condition information exists, the CPU 101 sends the image IDs andimaging-time information of the individual captured images to the clientapparatus 2. Then, the CPU 101 exists the processing routine.

FIG. 12 is a flowchart of a processing routine that is executed in stepS206 described earlier in response to an image obtaining requesttransmitted from the client apparatus 2.

First, in step S401, the CPU 101 decodes a packet of the image obtainingrequest, transmitted from the client apparatus 2. Then, in step S402,the CPU 101 extracts the image ID of the captured image requested by theclient apparatus 2, included in the packet of the image obtainingrequest. Then, in step S403, the CPU 101 reads image data correspondingto the image ID from the image database 11, and sends the image data tothe client apparatus 2 via the communication network 3. The CPU 101 thenexits the processing routine.

FIG. 13 is a flowchart of a routine for handling a search reservationrequest, executed in step S208 described earlier.

First, in step S501, the CPU 101 decodes a packet of the searchreservation request, transmitted from the client apparatus 2. Then, instep S502, the CPU 101 extracts a camera GUID that serves asidentification information of the client apparatus 2 from the packet ofthe search reservation request, and also extractssearch-reservation-condition information (such as an imaging location,an imaging direction, a camera angle, and an imaging time). Then, instep S503, the CPU 101 stores the camera GUID and thesearch-reservation-condition information in the reservation informationdatabase 12 in association with each other. The CPU 101 then exits theprocessing routine.

FIG. 14 is a flowchart of a routine for handling an image uploadingrequest, executed in step S210 described earlier.

Firs, in step S601, the CPU 101 decodes a packet of the image uploadingrequest, transmitted from the client apparatus 2. Then, in step S602,the CPU 101 assigns identification information (an image ID) to theuploaded image included in the packet. When identification informationis already assigned to the uploaded image included in the packet of theimage uploading request transmitted from the client apparatus 2,obviously, the image ID itself may be used.

Then, in step S603, the CPU 101 stores the uploaded image data and metainformation in the image server 1 in association with each other on thebasis of the image ID assigned in step S602.

Then, in step S604, the CPU 101 searches the reservation informationdatabase 12 for a search reservation request using the meta informationstored in the image database 11 in the current session. Then, in stepS605, the CPU 101 checks whether search-reservation-conditioninformation included in the search reservation request matches the metainformation of the image data stored in the current session.

When matching search reservation requests are detected in step S605, instep S606, the CPU 101 obtains all the camera GUIDs of the matchingsearch reservation requests, stored in the reservation informationdatabase 12.

In step S607, the CPU 101 stores all the camera GUIDs obtained in stepS606 and the image ID to send in the image-transmission-queue storageunit 15. The CPU 101 then exits the processing routine. When no matchingsearch reservation request is detected in step S605, the CPU 101immediately exists the processing routine.

As described above, according to this embodiment, the concept of imagingwith a camera that it is not possible to capture an image of the past orthe future is radically revoked, and it becomes possible to virtuallyprovide a user with an experience of capturing images beyond restrictionof time in addition to just capturing an image of the present.

In view of the explosive increase in the volume of image contentcaptured by individual users in accordance with the recent rapid spreadof digital cameras and camera-equipped cellular phones, this embodimentcould potentially develop totally new ways of using images through theuse of the image content resources and change the culture of enjoyingcapturing images.

In the embodiment described above, a search range regarding imaging timeis defined by a certain range instead of a point of time. Similarly,regarding imaging location, imaging direction, altitude, and cameraangle, instead of using values detected by sensors or the like directlyas search-condition information, regarding each of these parameters, acertain range with respect to a value detected by a sensor or the likemay be used as search-condition information. In that case, for each ofthe imaging location, the imaging direction, the altitude, and thecamera angle, a fixed search range may be predefined in advance, or theuser may be allowed to specify a search range similarly to the case ofimaging time described earlier.

Thus, for example, instead of specifying an imaging direction of Northas a search condition, it is possible to specify a range of imagingdirection from North East to North West. By increasing the search range,the number of images matching the search condition increases.

Although the embodiment has been described in the context of a casewhere still images are captured by a digital camera, application to acase where moving images are captured is also possible.

Although the embodiment is described in the context of a digital camera,application to a camera-equipped cellular phone terminal is alsopossible. Furthermore, application to a personal digital assistant (PDA)or a portable personal computer including a camera is also possible.

It is also possible to receive the image providing service throughregistration of membership in an image providing service company havingan image server. In that case, a GUID need not be assigned to a clientapparatus, and membership identification information such as amembership number may be used instead of a GUID.

Although the client apparatus in the embodiment described above includesan imaging unit, an imaging unit need not necessarily be included. Forexample, a PDA or a personal computer may send a search requestincluding search-condition information such as an imaging time, animaging location, and an imaging direction input by a user to an imageserver and receive search-result information from the image server.

The method of providing a requested image from an image server is notlimited to sending image data via a communication network to a clientapparatus as in the embodiment described above, and a printout of animage may be delivered to a user of a client apparatus, for example, bymail.

As for search-condition information, information for identifying animage other than imaging-time information may be of any type as long asthe information is accumulated in the image server as meta information.For example, when the user wishes to include the name of a location orarchitecture, such as “Asakusa”, “Kaminarimon”, or “Tokyo Tower” to animage captured by the user in meta information, searching based on thesenames becomes possible.

The image server or the client apparatus may have a function ofperforming image recognition on a captured image, and, when an imageincluding a specific architecture is recognized, automaticallyregistering the name of the architecture in meta information inassociation with the image data.

It should be understood by those skilled in the art that variousmodifications, combinations, sub-combinations and alterations may occurdepending on design requirements and other factors insofar as they arewithin the scope of the appended claims or the equivalents thereof.

1. A time-shift image distribution system comprising: an image server;and a time-shift image requesting apparatus configured to request theimage server to provide a time-shift image of a non-present time, thetime-shift image requesting apparatus being connected to the imageserver via a communication network; wherein the image server comprises:first communication means for carrying out communications with thetime-shift image requesting apparatus via the communication network, animage database configured to store image data of captured images inassociation with meta information including information representingimaging times and information for identifying subject images captured,searching means for searching the image database based on a searchrequest received from the time-shift image requesting apparatus via thefirst communication means, the search request at least includinginformation representing an imaging time and information for identifyinga subject image as search-condition information, the searching meanssearching the image database for image data of a captured image matchingthe search-condition information, and image providing means forproviding image data of a captured image detected by the searching meansto the time-shift image requesting apparatus, and wherein the time-shiftimage requesting apparatus comprises: second communication means forcarrying out communications with the image server via the communicationnetwork, and means for sending a search request including informationrepresenting an imaging time and information for identifying a subjectimage as search-condition information to the image server via the secondcommunication means.
 2. The time-shit image distribution systemaccording to claim 1, wherein the information representing the imagingtime, included in the search-condition information, represents a pasttime, wherein the image providing means of the image server isconfigured to send the image data of the captured image detected by thesearching means as matching the search-condition information to thetime-shift image requesting apparatus via the communication networkusing the first communication means, and wherein the time-shift imagerequesting apparatus further comprises means for receiving the imagedata transmitted from the image server via the communication network andfor displaying an image corresponding to the image data.
 3. Thetime-shift image distribution system according to claim 1, wherein theinformation representing the imaging time, included in thesearch-condition information, represents a past time, wherein the imageserver further comprises means for sending information at leastincluding information representing a presence or absence of a subjectimage matching the search-condition information to the time-shift imagerequesting apparatus as a result of searching by the searching means,wherein the image providing means is configured to execute processingfor providing the time-shift image requesting apparatus with the imagedata of the captured image detected by the searching means in responseto an image obtaining request transmitted from the time-shift imagerequesting apparatus, and wherein the time-shift image requestingapparatus further comprises means for displaying the informationrepresenting the presence or absence of a subject image matching thesearch-condition information on a display screen and means for sending arequest for obtaining the captured image matching the search-conditioninformation.
 4. The time-shift image distribution system according toclaim 1, wherein the image database of the image server is configured toallow adding and accumulating image data of new captured images, and theinformation representing the imaging time, included in thesearch-condition information, represents a future time, and wherein theimage server further comprises means for saving the search request as asearch reservation request, and the searching means searches the imagedatabase for image data of a captured image matching thesearch-condition information of the search reservation request.
 5. Thetime-shift image distribution system according to claim 1, wherein theinformation for identifying a subject image, included in thesearch-condition information, at least includes information representingan imaging location.
 6. The time-shift image distribution systemaccording to claim 5, wherein the time-shift image requesting apparatusfurther comprises location-information obtaining means for obtaininggeographical-location information representing a geographical location,and the time-shift image requesting apparatus is configured to sendlocation-range information to the image server as the informationrepresenting the imaging location, the location-range informationrepresenting a location range with reference to the geographicallocation represented by the geographical-location information obtainedby the location-information obtaining means.
 7. The time-shift imagedistribution system according to claim 6, wherein the time-shift imagerequesting apparatus further comprises direction detecting means fordetecting a direction in addition to the location-information obtainingmeans for obtaining geographical-location information, and thetime-shift image requesting apparatus is configured to senddirection-range information in addition to the location-rangeinformation to the image server as the information for identifying asubject image, included in the search-condition information, thedirection-range information representing a direction range withreference to the direction detected by the direction detecting means. 8.The time-shift image distribution system according to claim 7, whereinthe time-shift image requesting apparatus further comprises user inputmeans for allowing a user to set and change the location range and thedirection range.
 9. The time-shift image distribution system accordingto claim 6, wherein the time-shift image requesting apparatus furthercomprises: an imaging device, a display having a display screen, meansfor sending the search request to the image server via the communicationnetwork at a timing before a shutter button is pressed, the informationrepresenting the imaging time, included in the search-conditioninformation, representing a past time, means for receiving informationat least including a presence or absence of a captured image matchingthe search-condition information, transmitted from the image server viathe communication network as a result of searching, and for displayingthe information on the display screen of the display, means for sendinga request for obtaining the captured image matching the search-conditioninformation according to the result of searching to the image server viathe communication network when the shutter button is pressed, and meansfor displaying the captured image matching the search-conditioninformation, transmitted from the image server via the communicationnetwork, on the display screen, and wherein the image server furthercomprises means for sending information at least including informationrepresenting the presence or absence of a captured image matching thesearch-condition information to the time-shift image requestingapparatus via the communication network as a result of searching by thesearching means, based on the search request transmitted from thetime-shift image requesting apparatus, and wherein the image providingmeans is configured to send image data of the captured image to thetime-shift image requesting apparatus via the communication network, thecaptured image being detected by the searching means in response to theimage obtaining request transmitted from the time-shift requestingapparatus.
 10. The time-shift image distribution system according toclaim 9, wherein the time-shift image requesting apparatus furthercomprises means for actually carrying out imaging by the imaging devicewhen the shutter button is pressed, and for uploading image data of acaptured image obtained by the imaging to the image server together withmeta information at least including information representing a date ofimaging, an imaging location, and an imaging direction when uploading tothe image server is permitted, and wherein the image server includesmeans for accumulating the uploaded image data and meta information ofthe captured image in association with each other in the image database.11. The time-shift image distribution system according to claim 6,wherein the time-shift image requesting apparatus further comprises: animaging device, a display having a display screen, and means for sendingthe search request to the image server via the communication network ata timing when a shutter button is pressed, the information representingthe imaging time, included in the search-condition information,representing a future time, and wherein the image server includes meansfor saving the search request transmitted from the time-shift imagerequesting apparatus as a search reservation request, and the searchingmeans searches the image database for image data of a captured imagematching the search-condition information in the search reservationrequest.
 12. A time-shift image distribution method executed by an imageserver and a time-shift image requesting apparatus connected via acommunication network, the image server comprising an image databaseconfigured to accumulate image data of captured images in associationwith meta information including information representing imaging timesand information for identifying subject images, in which the time-shiftimage requesting apparatus requests the image server to provide atime-shift image of a non-present time to receive the time-shift imagefrom the image server, the time-shift image distribution methodcomprising the steps of: establishing, by the time-shift imagerequesting apparatus, a communication path for carrying outcommunications with the image server via the communication network;sending, by the time-shift image requesting apparatus, a search requestto the image server through the communication path established, thesearch request including information representing an imaging time andinformation for identifying a subject image as search-conditioninformation; searching, by the image server, the image database forimage data of a captured image matching search-condition informationincluded in a search request received from the time-shift imagerequesting apparatus via the communication path, the search-conditioninformation including information representing an imaging time andinformation for identifying a subject image; and providing, by the imageserver, the image data of the captured image, detected by the searching,to the time-shift image requesting apparatus.
 13. A time-shift imagerequesting apparatus, connected to an image server via a communicationnetwork, for requesting the image server to provide a time-shift imageof a non-present time, the time-shift image requesting apparatuscomprising: communication means for carrying out communications with theimage server via the communication network; and means for sending asearch request to the image server via the communication means, thesearch request including information representing an imaging time andinformation for identifying a subject image.
 14. The time-shift imagerequesting apparatus according to claim 13, wherein the informationrepresenting the imaging time, included in search-condition information,represents a past time, and wherein the time-shift image requestingapparatus further comprises means for receiving image data of thecaptured image matching the search-condition information via thecommunication means, the image data being transmitted from the imageserver via the communication network, and for displaying an imagecorresponding to the image data.
 15. The time-shift image requestingapparatus according to claim 13, wherein the information representingthe imaging time, included in the search-condition information,represents a past time, and wherein the time-shift image requestingapparatus further comprises: means for receiving information includingat least information representing a presence or absence of a capturedimage matching the search-condition information, transmitted from theimage server via the communication network, and displaying theinformation on a display screen, means for sending a request forobtaining the captured image matching the search-condition information;and means for receiving image data of the captured image matching thesearch-condition information, transmitted in response to the obtainingrequest from the image server via the communication network.
 16. Thetime-shift image requesting apparatus according to claim 13, wherein theinformation representing the imaging time, included in thesearch-condition information, represents a future time.
 17. Thetime-shift image requesting apparatus according to claim 13, wherein theinformation for identifying a subject image, included in thesearch-condition information, at least includes information representingan imaging location.
 18. The time-shift image requesting apparatusaccording to claim 17, further comprising location-information obtainingmeans for obtaining geographical-location information representing ageographical location, wherein the time-shift image requesting apparatusis configured to send location-range information to the image server asthe information representing the imaging location, the location-rangeinformation representing a location range with reference to thegeographical location represented by the geographical-locationinformation obtained by the location-information obtaining means. 19.The time-shift image requesting apparatus according to claim 18, furthercomprising direction detecting means for detecting a direction inaddition to the location-information obtaining means for obtaininggeographical-location information, wherein the time-shift imagerequesting apparatus is configured to send direction-range informationin addition to the location-range information to the image server as theinformation for identifying a subject image, included in thesearch-condition information, the direction-range informationrepresenting a direction range with reference to the direction detectedby the direction detecting means.
 20. The time-shift image requestingapparatus according to claim 19, further comprising user input means forallowing a user to set and change the location range and the directionrange.
 21. The time-shift image requesting apparatus according to claim18, further comprising: an imaging device, a display having a displayscreen, means for sending the search request to the image server via thecommunication network at a timing before a shutter button is pressed,the information representing the imaging time, included in thesearch-condition information, representing a past time, means forreceiving information at least including a presence or absence of acaptured image matching the search-condition information, transmittedfrom the image server via the communication network as a result ofsearching, and for displaying the information on the display screen ofthe display, means for sending a request for obtaining the capturedimage matching the search-condition information according to the resultof searching to the image server via the communication network when theshutter button is pressed, and means for displaying the captured imagematching the search-condition information, transmitted from the imageserver via the communication network, on the display screen.
 22. Thetime-shift image requesting apparatus according to claim 21, furthercomprising means for actually carrying out imaging by the imaging devicewhen the shutter button is pressed, and for uploading image data of acaptured image obtained by the imaging to the image server together withmeta information at least including information representing a date ofimaging, an imaging location, and an imaging direction when uploading tothe image server is permitted.
 23. The time-shift image requestingapparatus according to claim 18, further comprising: an imaging device,a display having a display screen, and means for sending the searchrequest to the image server via the communication network at a timingwhen a shutter button is pressed, the information representing theimaging time, included in the search-condition information, representinga future time.
 24. An image server, connected to a time-shift imagerequesting apparatus via a communication network, for receiving arequest for providing a time-shift image of a non-present time from thetime-shift image requesting apparatus and providing the time-shift imageto the time-shift image requesting apparatus, the image servercomprising: communication means for carrying out communications with thetime-shift image requesting apparatus via the communication network; animage database configured to accumulate image data of captured images inassociation with meta information including information representingimaging times and information for identifying subject images; searchingmeans for searching the image database based on a search requestreceived from the time-shift image requesting apparatus via thecommunication means, the search request at least including informationrepresenting an imaging time and information for identifying a subjectimage as search-condition information, the searching means searching theimage database for a captured image matching the search-conditioninformation; and image providing means for providing image data of thecaptured image detected by the searching means to the time-shift imagerequesting apparatus.
 25. The image server according to claim 24,wherein the information representing the imaging time, included in thesearch-condition information, represents a past time, and wherein theimage server further comprises means for sending information includingat least information representing the presence or absence of a capturedimage matching the search-condition information to the time-shift imagerequesting apparatus as a result of searching by the searching means.26. The image server according to claim 24, wherein the image databaseis configured to allow adding and accumulating image data of newcaptured images, and the information representing the imaging time,included in the search-condition information, represents a future time,and wherein the image server includes means for saving the searchrequest as a search reservation request, and the searching meanssearches the image database for image data of a captured image matchingthe search-condition information of the search reservation request. 27.The image server according to claim 24, wherein the information foridentifying a subject image, included in the search-conditioninformation, at least includes information representing an imaginglocation.
 28. The image server according to claim 27, wherein theinformation for identifying a subject image, included in thesearch-condition information, includes location-range informationrepresenting a location range with reference to a geographical locationof the time-shift image requesting apparatus and direction-rangeinformation representing a direction range with reference to a directionof the time-shift image requesting apparatus.
 29. A time-shift imagedistribution system comprising: an image server; and a time-shift imagerequesting apparatus configured to request the image server to provide atime-shift image of a non-present time, the time-shift image requestingapparatus being connected to the image server via a communicationnetwork; wherein the image server comprises: a first communication unitconfigured to carry out communications with the time-shift imagerequesting apparatus via the communication network, an image databaseconfigured to store image data of captured images in association withmeta information including information representing imaging times andinformation for identifying subject images captured, a searching unitconfigured to search the image database based on a search requestreceived from the time-shift image requesting apparatus via the firstcommunication unit, the search request at least including informationrepresenting an imaging time and information for identifying a subjectimage as search-condition information, the searching unit searching theimage database for image data of a captured image matching thesearch-condition information, and an image providing unit configured toprovide the image data of the captured image detected by the searchingunit to the time-shift image requesting apparatus, and wherein thetime-shift image requesting apparatus comprises: a second communicationunit configured to carry out communications with the image server viathe communication network, and a unit configured to send a searchrequest including information representing an imaging time andinformation for identifying a subject image as search-conditioninformation to the image server via the second communication unit.
 30. Atime-shift image requesting apparatus, connected to an image server viaa communication network, for requesting the image server to provide atime-shift image of a non-present time, the time-shift image requestingapparatus comprising: a communication unit configured to carry outcommunications with the image server via the communication network; anda unit configured to send a search request to the image server via thecommunication unit, the search request including informationrepresenting an imaging time and information for identifying a subjectimage.
 31. An image server, connected to a time-shift image requestingapparatus via a communication network, for receiving a request forproviding a time-shift image of a non-present time from the time-shiftimage requesting apparatus and providing the time-shift image to thetime-shift image requesting apparatus, the image server comprising: acommunication unit configured to carry out communications with thetime-shift image requesting apparatus via the communication network; animage database configured to accumulate image data of captured images inassociation with meta information including information representingimaging times and information for identifying subject images; asearching unit configured to search the image database based on a searchrequest received from the time-shift image requesting apparatus via thecommunication unit, the search request at least including informationrepresenting an imaging time and information for identifying a subjectimage as search-condition information, the searching unit searching theimage database for a captured image matching the search-conditioninformation; and an image providing unit configured to provide imagedata of the captured image detected by the searching unit to thetime-shift image requesting apparatus.